So my brown porter has spent a little under a month in primary and is ready for bottling, my plan is to add 4 oz of cold brew coffee to 2.5 gallons of my 5 gallon batch and just bottling the other half straight.

Two questions:
Will 4 oz of coffee be too much for my 2.5 gallon batch?
Is adding the cold brew coffee during bottling okay? Any sanitation issues or other problems I should be concerned with?